Continuously variable transmissions are increasingly used. This is a result of the advantage of CVTs which is that shift shock is avoided by enabling speed ratios to be varied in a continuous fashion.
However, conventional continuously variable transmissions which are well known at present have problems that whole shift range is so limited, deteriorating fuel consumption ratio and driving performance. The U.S. Pat. No. 4,772,247 discloses such a continuously variable transmission.
For the foregoing reasons, there is a need for a continuously variable transmission which has an enlarged shift range to improve the fuel efficiency and driving performance.